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Low‐dimensional metal halides (LDMHs) represent a promising class of materials in various luminescent applications because of their self‐trapped exciton (STE) emissions with unique properties such as broad luminescence spectra, large Stokes shift, and high color rendition. LDMHs at the molecular level can be constructed, including 2D layers, 1D chains, and 0D clusters assembled by polyhedra units, all of which exhibit significantly different luminescence properties from 3D MHs. The dimensional regulation of LDMHs has been explored for years, including the choice of organic cations, modulating electron‐phonon coupling effect, and adding external temperature and pressure. Herein, this review discusses the synergy between structural engineering and solvent effects for LDMHs, including the emission mechanisms for LDMHs and the roles solvent molecules play in regulating the dimensions. In addition, challenges and opportunities for LDMHs are discussed to shed light on the future development of novel materials with multifunctional optical properties suitable for practical applications. [ABSTRACT FROM AUTHOR]

Low‐dimensional lead‐based metal halide perovskites (MHPs) have many exceptional photoelectric capabilities thanks to the 6 s2 electron structure of lead ion (Pb2+). Pb2+′s toxicity, however, has prevented its widespread development and use. Finding ions in the valence layer that have a comparable electrical structure thus makes sense as Pb2+ replacements. In this work, all inorganic zero‐dimensional (0D) Cs3BiCl6 single crystal was synthesized by the anti‐solvent crystallization method. There is no obvious photoluminescence (PL) phenomenon for Cs3BiCl6 at room temperature (RT). It is found that the extremely strong exciton‐phonon interaction leads to seriously non‐radiative recombination. After doping with Sb3+, Cs3BiCl6: Sb achieved broadband emission with a significant Stokes shift, the photoluminescence quantum yield (PLQY) up to 15.85 %, which has a microsecond PL decay lifetime and excellent environmental stability. Systematic spectroscopic characterizations unveil the PL mechanism of Cs3BiCl6: Sb is self‐trapped excitons (STEs) emission, and theoretical calculation revealed the indirect bandgap properties of Cs3BiCl6 and Cs3BiCl6: Sb. [ABSTRACT FROM AUTHOR]

Zero‐dimensional metal halides have attracted much attention due to their attractive photoelectric properties. Here, we propose a new strategy of synthesizing metal halides crystals by recrystallization in water. The as‐synthesized Cs2InCl5(H2O)‐orange crystals are dissolved and recrystallized in water (Cs2InCl5(H2O)‐blue), with its photoluminescence (PL) changing from orange to blue, both of which are derived from self‐trapping excitons (STEs). The time‐resolved photoluminescence (TRPL) spectrum of Cs2InCl5(H2O)‐blue shows that it has an ultralong lifetime up to milliseconds (τ=52.98 ms), which is expected to be applied in biological sensors. The photoluminescence quantum yield (PLQY) increases from 2.25% to 11.61% in the self‐assembly process. By using a post‐doping method, the PL of crystals turns into red when we introduce Mn2+ as dopant while there is no obvious change upon using a traditional solvent‐thermal method. Recrystallization in water and post‐doping provide a new perspective for the synthesis and doping of metal halides. [ABSTRACT FROM AUTHOR]

A uranyl compound [(UO2)(C10H8N2O2)2][HPW12O40] has been hydrothermally synthesized (150 °C for 72 h) in the presence of typical Keggin‐phosphotungstic acid. This compound exhibits a regular layered structure which is composed of [UO2]2+ and bridging ligand 4,4'‐bipyridine‐N‐dioxide (4,4'‐BPDO). The nanosized cavities are occupied by Keggin‐anions [HPW12O40]2– through covalent bonds and hydrogen bonds, in order to hold the charge equilibrium and enhance the stability of the structure. The adsorption properties of this compound have been primarily investigated. The results indicate that the incorporation of Keggin‐anions plays an important role in the fast capture of cationic dye MB+. Compound 1 is the first case of uranyl coordination network decorated by POMs, which evidently provides a feasible strategy for controlling the structural connectivity and functionality of uranyl organic framework. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) of 25 % mainly have SnO2 or TiO2 as electron‐transporting layers (ETLs). Now, zinc titanate (ZnTiO3, ZTO) is proposed as mesoporous ETLs owing to its weak photo‐effect, excellent carrier extraction, and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150 °C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2‐mesorporous ZTO electrode and Spiro‐OMeTAD layer achieved the PCE of 20.5 %. The PSCs retained more than 95 % of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95 % of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5 G illumination (100 mW cm−2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. [ABSTRACT FROM AUTHOR]

Although planar‐structured perovskite solar cells (PSCs) have power conversion efficiencies exceeding 24%, the poor photostability, especially with ultraviolet irradiance (UV) severely limits commercial application. The most commonly‐used TiO2 electron selective layer has a strong photocatalytic effect on perovskite/TiO2 interface when TiO2 is excited by UV light. Here a UV‐inert ZnTiO3 is reported as the electron selective layer in planar PSCs. ZnTiO3 is a perovskite‐structured semiconductor with excellent chemical stability and poor photocatalysis. Solar cells are fabricated with a structure of indium doped tin oxide (ITO)/ZnTiO3/Cs0.05FA0.81MA0.14PbI2.55Br0.45/Sprio‐MeOTAD/Au. The champion device exhibits a stabilized power conversion efficiency of 19.8% with improved photostability. The device holds 90% of its initial efficiency after 100 h of UV soaking (365 nm, 8 mW cm−2), compared with 55% for TiO2‐based devices. This work provides a new class of electron selective materials with excellent UV stability in perovskite solar cell applications. [ABSTRACT FROM AUTHOR]

Low‐dimensional lead‐based metal halide perovskites (MHPs) have many exceptional photoelectric capabilities thanks to the 6 s2 electron structure of lead ion (Pb2+). Pb2+′s toxicity, however, has prevented its widespread development and use. Finding ions in the valence layer that have a comparable electrical structure thus makes sense as Pb2+ replacements. In this work, all inorganic zero‐dimensional (0D) Cs3BiCl6 single crystal was synthesized by the anti‐solvent crystallization method. There is no obvious photoluminescence (PL) phenomenon for Cs3BiCl6 at room temperature (RT). It is found that the extremely strong exciton‐phonon interaction leads to seriously non‐radiative recombination. After doping with Sb3+, Cs3BiCl6: Sb achieved broadband emission with a significant Stokes shift, the photoluminescence quantum yield (PLQY) up to 15.85 %, which has a microsecond PL decay lifetime and excellent environmental stability. Systematic spectroscopic characterizations unveil the PL mechanism of Cs3BiCl6: Sb is self‐trapped excitons (STEs) emission, and theoretical calculation revealed the indirect bandgap properties of Cs3BiCl6 and Cs3BiCl6: Sb. [ABSTRACT FROM AUTHOR]

In just over a decade, certified single-junction perovskite solar cells (PSCs) boast an impressive power conversion efficiency (PCE) of 26.1%. Such outstanding performance makes it highly viable for further development. Here, we have meticulously outlined challenges that arose during the industrialization of PSCs and proposed their corresponding solutions based on extensive research. We discussed the main challenges in this field including technological limitations, multi-scenario applications, sustainable development, etc. Mature photovoltaic solutions provide the perovskite community with invaluable insights for overcoming the challenges of industrialization. In the upcoming stages of PSCs advancement, it has become evident that addressing the challenges concerning long-term stability and sustainability is paramount. In this manner, we can facilitate a more effective integration of PSCs into our daily lives., (© 2024. The Author(s).)

Dimension growth of metal halides is important for its properties and applications. However, such dimension control of the metal halides is rarely reported in the literature and the growth mechanism is not clear yet. A minute difference of solvent properties can tremendously alter the process of nucleation and growth of crystals. Herein, an intriguing phenomenon of dimension tuning for Ag-based metal halides is reported. The 1D Cs 2 AgCl 3 crystals can be obtained in pure DMF while the 2D CsAgCl 2 crystals are obtained in pure DMSO. Both exhibit bright yellow emission, which are derived from self-trapping excitons (STEs). The photoluminescence quantum yield (PLQY) of Cs 2 AgCl 3 (1D) and CsAgCl 2 (2D) are 28.46 % and 20.61 %, respectively. In order to understand the mechanism of the dimension change, additional solvents (N,N-dimethylacetamide, DMAC, 1,3-Dimethyl-Tetrahydropyrimidin-2(1H)-one, DMPU) are also selected to process the precursor for crystal growth. By comparing the functional group, dielectric constant, and donor number among the four solvents, we find the donor number plays the predominant role in nucleation process for Cs 2 AgCl 3 and CsAgCl 2 . This research reveals the relationship between coordination ability of the solvent and the dimension of metal halides., (© 2023 Wiley-VCH GmbH.)

Optical materials play a momentous role in anti-counterfeiting field, such as authentication, currency and security. The development of tunable optical properties and optical responses to a range of external stimuli is quite imperative for the growing demand of optical anti-counterfeiting technology. Metal halide perovskites have attracted much attention of researchers due to their excellent optical properties. In addition, co-doping methods have been gradually applied to the research of metal halide perovskites, by which more abundant luminescence phenomena can be introduced into the host perovskite. Herein, the ns 2 ions of bismuth (Bi 3+ ) and antimony (Sb 3+ ) ions co-doped zero-dimensional Cs 2 SnCl 6 metal halide with an excitation-wavelength-dependent emission phenomenon is synthesized as an efficient multimodal luminescent material, the luminescence of which is tunable and covers a wide region of color. What's more, a dynamic dual-emission phenomenon is captured when the excitation wavelength changes from 320 nm to 420 nm for Cs 2 SnCl 6 :Bi 0.08 Sb 0.12 crystals. Moreover, the Bi 3+ and Sb 3+ doped metal halide material shows great enhancement in solvent resistance and thermal stability compared to the pristine Cs 2 SnCl 6 . The admirable stability and distinguishable photoluminescence (PL) phenomenon of this all-inorganic metal halide has great potential to be applied in optical anti-counterfeiting technology. Furthermore, the co-doping method can accelerate the discovery of new luminescence phenomena in original metal halide perovskites., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)